1. Field of the Invention
The present invention relates to a gas level measuring device and, particularly, to a modular gas level measuring device in a liquefied gas tank.
2. Description of the Related Art
U.S. Pat. No. 5,479,820 shows a cryogenic gauge for measuring fluid level, especially cryogenic fluids. The gauge utilizes a float assembly which can be adjusted for the densities of various fluids. The float assembly includes a head assembly with a passageway to receive the upper portion of a lift rod assembly. The lift rod assembly includes a spring attached at the upper end to the head and attached at the lower end to a spring guide. A lift rod is mounted adjustably on the spring guide. The upper end of the lift rod has attached a magnet, and the lower end of the lift rod has attached a displacement member. The upper end of the lift rod is received in the passageway of the head. Attached to the head adjacent to the passageway is a dial assembly adjustably mounted in relation to the passageway of the head.
Conventionally, one float assembly size is made for one pressure vessel size. Therefore, different float assemblies are made in different molds. However, it is expensive to build a mold.
U.S. Pat. No. 5,479,820 shows a float that is made up of a set of washer-like sections which are held in position by lock nuts. The size and dimension of the float may be expanded or contracted by removing or adding washer-like sections. Although the float includes modular washer-like sections, a lift rod of one size is not feasible. Different amounts of washer-like sections would be utilized in small pressure vessels in order to obtain accurate measurements. However, the lift rod for the small pressure vessel would be too short to receive more washer-like sections in the big pressure vessel.
The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art.